Things like this thread are why atheism isn't really any more rational than spiritual belief. Scenarios are being offered under the de facto assumption that some kind of afterlife is impossible. "Well, this may be unlikely, or I can't think of anything right now, but I know it's not THAT." It's no different than the way religions bend over backwards to explain things in a way that incorporates their dogma.
Thesis: Some kind of an afterlife is possible.
Afterlife: Existence after the death of our body. Existence must be similar to the existence we experience on earth either with regard to our physical or psychological activities.
Reasons to believe that our thesis is true: What people report to have experienced at the time when physicians thought that they were dead is reminiscent of life after death.
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Problem: There is life after death only if the physicians were corrected in declaring that the people who have reported the aforementioned experiences were dead and if the aforementioned reported experiences are true.
1)Do we know if the people in question were truly dead?
We do not know such a thing, as the articles Jack Flak has cited suggest that knowledge of the patient's inactive heart does not guarantee knowledge of the patient's inactivity of the brain.
2)Do we know if the aforementioned experiences were true? The visions depicted in such experiences were highly structured, or they included events that follow a clear pattern, exactly like events follow a pattern in a story depicting real-life occurences. We know that in order to think in a structured fashion we must be conscious, as structured thinking by its own definition requires that we organize our thoughts. We know that when we are unconscious we experience visions which are not structured. However, when we proceed to explain our visions (in this case the visions we have experienced in our dreams) to others, we bring structure to our visions. Very often we alter the content of our visions without knowing we have done so.
The psychological principles I wish to establish is as follows, our visions that we have not carefully organized cannot be clearly remembered as in themselves they lack structure. To examplify this matter, consider how we struggle to remember a random group of letters, but if we were told that these letters are an acronym that represent an idea that we are clearly aware of (or that we are told that the letters have a pattern), it would be easier for us to remember such a group of letters.
As aforementioned, what we see when we are unconscious cannot be structured and therefore is almost always altered. It is altered in two regards, much like our dreams tend to be altered. We misrepresent the content of what we have envisaged, and because we do not have a clear idea of what exactly we have envisaged, we tend to introduce additional material to our visions (material that has not occured in what we have seen) or neglect to recollect some of the material we have seen.
Thus, this shows that it is unlikely that the visions the people in question have experienced are true.
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Additional notes on the visions of the people who claimed to have returned from the dead: It is very natural for us to believe in what strikes us as most pleasant. Wishful thinking, for this reason is very common among most people. Consider how, 5 months from now we may think that the opinions we have expressed to other people in our letters are profound and interesting. Yet, upon re-reading such letters, we would observe that this was not the case. Or for example, how an athlete may think he has performed well in a competitive event, yet upon reviewing the game on television, it would become obvious that this was not the case.
Moreover, consider how many elaborate interpretation we concoct for our dreams and how well structured our stories (that purport to depict what we have experienced in our dreams) tend to be. Yet it is clear to us that such structure could be possible only through conscious thinking.
One now is tempted to ask the following question; suppose John was declared dead at 7pm. At 7:05 PM the nurse said that it is raining outside. At 7:10 PM the doctor took off his mask and placed it on the highest shelf in the room.
John has regained consciousness at 7:20 PM and states what the doctor and the nurse intepret as the following "The nurse said it was raining outside and the doctor put his mask on the highest shelf in the room."
Lets assume that John was not truly dead. His brain remained active to a certain degree. It is not clear to what degree the brain could be active when his heart ceases to work. It is conceivable however, that his brain would be active enough to allow him to hear what has been said, as very often we can recollect what has been said when we are only partially unconscious.
Hence, John may have been able to report accurate information with regard to what has been said. Yet, it certainly seems doubtful that he would be able to report exactly what others have said or what others have done when he was unconscious, as having such clear recollections requires structured thinking. Such structured thinking is possible only through conscious activity.
At this point I wish to draw the reader's attention to the phenomenon of wishful thinking. John may have had (and likely had if at all) only partial perceptions of what has happened when he was unconscious and with limited success provided structure for his perceptions. As a result of this what he had stated to the nurse and the doctor was only vaguely reminiscent of occurences that took place when he was unconscious.
Moreoever, its possible that John was completely dead and had no perceptions at the time when he was unconscious. The perceptions he had were collected before he had died and were stored in his memory. He has retrieved such perceptions after he has regained consciousness.
The doctor and the nurse, eager to believe in life after death envisage that what he said obviously matches what has occured when he was unconscious. It is also the case that John himself was eager to believe that there is life after death and his experiences confirm such a proposition. Therefore, wishful thinking on his part could easily convince him that what he has experienced when he was unconscious supports the proposition that life after death is possible. It is very easy for John to think in a wishful fashion under these circumstances because his unconscious experiences are unstructured and therefore can be easily diluted, it is also his nature to think wishfully. Therefore it follows that because John thinks wishfully and it is easy for him distort the content of his visions, he will most likely alter the visions he has experienced to better fit the conclusions with regard to such visions that he wishes to accept.
Hence, the experiences that John has shared most likely had more in common with our recollections of dreams and all other of our unconscious psychological experiences. By virtue of John's attempt to bring structure to his visions and wishful thinking on his part, as well as those who have attempted to interpret his visions, a very elaborate and propitious to ourselves explanation of his experiences has been concocted. Such an explanation, almost certainly, does not correspond to what John truly has experienced when he was unconscious.
It is unlikely that if this case was subjected to careful inquiry, that what John had stated corresponds closely to what has occured when he was unconscious.
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Summary:We do not have a reason to believe in the possibility of an afterlife because we do not know if any person who has communicated with us was truly dead and we do not have a reason to believe that their testimony is accurate, even if it was the case that such a person was truly dead.